Einstein got it all wrong?

Discussion in 'Physics & Math' started by scifes, Mar 26, 2011.

  1. Bearlingual Registered Member

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    What if a vehicle was made that pulled space/matter/light towards it? If we understood the power of a black hole better, maybe we could duplicate it.

    Basically, if you can't move an object across the rug at 100km/h, maybe you could pull the rug out from underneath the object at that speed? Then, maybe you can pull the rug while simultaneously pushing the object.

    I'm new here and just getting into science and math. I literally typed science forums in google and this came up.

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    I think it is foolish to say anything is impossible. History has taught us that if we are consistent at anything, it is being wrong. Keep an open mind I say!
     
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  3. OnlyMe Valued Senior Member

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    Only those distances that are measured between points in one's own frame of reference can be considered as real. When measuring distance defined in a frame of reference in motion relative to the observer, it will always appear length contracted when compared with measurements made from the moving frame.

    Basically distance has no real meaning unless it is measured between coordiantes in the observers coordinate system.
     
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  5. OnlyMe Valued Senior Member

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    Admitting that I have not read the whole of this reference , yet.., then first thing that comes to mind is that cosmic rays interact with the atmosphere all the way to the ground. This why neutrino detectors are buried in deep mines and antarctic ice. Before the initial assertion that muons generated by cosmic rays interacting with the upper atmosphere reach the ground can be accepted as fact, it has to be demonstrated that no lower atmospheric interaction generates muons.

    This comment is not intended as a challenge to the basic conclusions, or science generally. Just making note of an initial look at the reference. Could be answered later on.

    These mostly appear to be very good references. I am downloading the content to allow a more considered look when time allows.

    There is a question I have had involving some of the time dilation effects observed with GPS satellites. There are some observations of variations in radioactive decay rates that correspond to seasonal changes in the earth sun distance and solar flare activity. The earth sun distance variation is not as much a concern as solar flare activity, since atomic clocks on earth would be at least partially shielded. The concern I have is that if changes in solar activity can affect decay rates on earth, it could suggest a difference in the decay rates between a satellite and a location deep within the Earth's magnetic field.

    I could not find links to the original papers off hand but here is one that at least mentions the solar connection, http://news.stanford.edu/news/2010/august/sun-082310.html

    This is true. But it is an example of perceived distances. Until you get into general relativity, where space is dynamic and curved, distances are time independent. Velocity has no affect an real distances.

    Given two observers in two separate frames of reference and in motion relative to one another, both observers will measure distances defined from the others coordinate system as length contracted, while the same distances in their own coordinate system remain unchanged. The observed contractions are consistent with the Lorentz transformations.



    Special relativity also addresses length contraction of objects in motion, also consistent with the Lorentz transformations. Length contraction of a moving object is still theoretical but is supported by experiment and observation.
     
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  7. OnlyMe Valued Senior Member

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    If both a rod alined with the direction of a spaceship's motion and an observer are both inside the spaceship, the observer in the space ship does not experience length contraction of the ship or the rod.

    Essentially, since everything wemknow of in the universe is in some state of motion everything is length contracted. In the thought experiment where there is a stationary observer and an observer in motion, the observer, her/his space ship and the rod are length contracted relative to the stationary observer. In this case we can say that this is real length contraction because even though the earth may be in motion the motion or velocity of the space ship is in addition to the earth's motion.

    This is really the same issue that comes up in the twin paradox, just addressing length contraction rather than time dilation and aging. Without establishing some means of defining which observer is in motion relative to the other there is now way to know which is time dilated or length contracted, as a result of their relative velocity.
     
  8. Pete It's not rocket surgery Moderator

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    That idea does have some merit, since the measurement of the distance between two points in the rest frame of those points is indeed an invariant quantity, called the proper length.

    But, the same applies to the length of an object, so I still not sure why you distinguish the distance between points from the length of an object.


    Anyway, I don't know if there's any problem with considering proper length to be more "real" than moving length... but that point of view doesn't seem to lead to any measurable difference from the paradigm in which any length is a relative measurement of a path through spacetime.

    I don't think there's really a dramatic difference between SR and GR here. In both cases, distance is a relative measurement of a path through spacetime. In SR, the spacetime geometry is globally flat, while in GR it's only locally flat, but in both cases you can get a distance measure by dividing the path into pieces small enough to be approximately straight, and adding them up, I think.
    So in both SR and GR, velocity has no effect on proper distances, but definately affects relative distances. Both are measures of the underlying spacetime path.

    Anyway, I guess you can think of proper distances as "real" if you like, , but it might make communication difficult.
    Personally, I like to think of spacetime paths as more "real" than both distances and time measures, but it wouldn't surprise or concern me if there was yet another layer of "more real" underneath.

    I suppose I could quibble over the boundaries of 'theoretical', but whatever. Yes I agree. SR is pretty much defined by the Lorentz transformation, and is consistent with experiments in its domain (locally flat spacetime).

    Exactly the point of relativity. There seems to be no way of measuring whether is at rest, except relative to something else.
    So it seems reasonable to conclude that it simply doesn't matter whether something is "really" at rest or in motion, and that perhaps the notion of "at rest" doesn't actually have any meaning except as a relationship between objects.

    Right! And following that idea through, we find that it doesn't matter what we define to be the rest state in that scenario.
    • We can arbitrarily choose the initial state of motion for the twins.
    • We can even change our definitions part way through (so we could choose to have the traveling twin always at rest, for example).
    • SR will always give the same results for their ages when they meet again.
     
  9. Pete It's not rocket surgery Moderator

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    Good thought. I like your posts, because you test my amateur understanding of these things.
    The effect you describe is measured by counting cosmic ray-related particle events at different altitudes (image below from Cosmic Ray and Neutrino Physics), and the particle interaction models used to analyse and explain the results are also tested in ground-based accelerators.

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    It is good (imperative!) to think of other explanations for observations, of course, but as rpenner points out, if some phenomena is consistently well described by a parsimonious model, then I think we can afford to relax our suspicion somewhat, and begin to rely on the model rather than worrying too much about unconsidered confounders Especially since good scientists are excellent at smashing ideas to bits.

    Any idea has developed into a testable physical model and survived long enough to gain mainstream notice is going to be pretty robust to begin with, but even then most models don't survive the hard worldwide hammering that gets laid on. So you can be very sure that a hard physics model that has managed to filter down into undergraduate texts is going to be damn near unbreakable. That shouldn't stop us students and amateurs to think of ways to break it, of course. We should just temper our arrogance and keep an open mind about our own fallibility, and also do the due diligence to find out who has thought of our objections before and how they were accounted for.

    Evidence for Solar Influences on Nuclear Decay Rates (PD Sutton, 2010. Arxiv, High Energy Physics - Phenomenology)
    Again, a good thought, except that GPS clocks are not governed by decay rates, but by electron transitions in Caesium-133 atoms. I don't know what factors influence those transitions, but this is very mature science and technology. And it would seem extremely unlikely that some unconsidered factor just happened to speed up atomic clocks in orbit by exactly the amount predicted by relativity, right?

    Edit:
    I've also just found that the Rubidium-87 standard atomic clock also has a long space history. If electron transitions are affected by solar radiation (or some other particle interaction confounder), then it would seem likely that the two standards would be affected by different amounts, right? So, we should be able to test within tight limits by looking for anomalous divergence between a Caesium-133 standard clock and a Rubidium-87 standard clock on the same spacecraft.

    I bet this has been done.
     
    Last edited: Apr 7, 2011
  10. OnlyMe Valued Senior Member

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    Length contraction was there original objective of the Lorentz Transformations. Einstein reinterpreted and expanded on his (Lorentz) work.

    I make a distinction between distances and objects because it seems clear to me that SR when comparing observations in different frames of reference, is laying a foundation from which to understand the difference in the way events are perceived and tools to reconcile the difference.

    Length contraction of an object in motion is more difficult to reconcile, precicely for the reasons you have pointed out. It appears to be the same as distance.

    I added the GR disclaimer only because once gravity is involved things can get even more complex.
     
  11. origin Trump is the best argument against a democracy. Valued Senior Member

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    I am not sure what you are trying to say. Are you saying that if a space ship were to fly by the moon that the ship would appear length contracted to an observer on the moon but the moon would not appear length contracted from the perspective of the ship?
     
  12. Janus58 Valued Senior Member

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    You're missing the point.

    What Relativity tells us is that any measurement we make (whether it is of time or space) is like one of those pictures. It is a "representation" of "reality" but not the only representation, nor is one representation any more valid or more accurate at portraying reality than another.

    To use the spaceship traveling from Earth to Sun example: The distance of 150,000,000 km from Earth to Sun as measured by someone at rest with respect to the Sun is like the full front picture of Capone, while the 75,000,000 km distance measured by someone at rest with respect to the spaceship is like the profile picture. Both accurately reflect "reality", just from different perspectives.

    So when two frames of reference come up with a different length of time and distance between two events, it isn't that they have different realities, or that one measures the one "true" reality and the other doesn't, but that they both are just measuring the same reality from a different perspective.
     
  13. Emil Valued Senior Member

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    I appeal to all mathematicians who in good faith.
    Please read carefully the link:
    Using the same reasoning as that presented in the link,using any of the options presented in the link.

    What would be the time required for a muon to travel from Earth to the Sun?
    Already beginning to tired arguing, which for me is obvious.
     
  14. Janus58 Valued Senior Member

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    In motion relative to what?.
    You still seem to be claiming the existance of some unique preferred frame to which all motion is measured. In the thought experiment, there si not a "stationary" observer and an observer "in motion", just two observers which have a relative motion with respect to each other, The length contractions each measures in the other are equally "real".
    Each is time dilated and length contracted as measured by the other, all that is needed to to know their relative velocity. The issue that proves to be the stumbling block for many in terms of the Twin paradox is the Simultaneity of Relativity, and its effect on the observations on the twin that changes inertial reference frames in order to join back up with his brother.
     
  15. Janus58 Valued Senior Member

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    1,789

    According to the Earth: 8 min 20 sec
    According to the Muon 7 sec.

    However, since the muon's life time, according to the Earth would be 0.00014 sec (much less than 8 min 20 seconds), and according to the muon would be 2e-6 sec (much less than 7 sec.), a muon would not last long enough to travel from Earth to Sun according to either.

    It is obvious to you in the way that it once was obivious to many that the world could not be a sphere because the people on the underside would fall off.
     
  16. Emil Valued Senior Member

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    No, it is according to the Earth 7 sec.
    No, it was measured on the Earth:τ = 2 × 10^-6s
     
  17. AlphaNumeric Fully ionized Moderator

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    I think it is laughable you talk about 'good faith' when you refuse to engage in discussion, haven't read anything on the subject and are profoundly ignorant on all relevant issues.

    Please read a book.

    You completely ignored my post discussing precisely that sort of thing, highly relativistic motion between the Sun and Earth. This demonstrates your talk of 'good faith' is nothing but empty words to try and make it seem like you're taking the moral high ground but you aren't.
     
  18. OnlyMe Valued Senior Member

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    3,914
    If the Lorentz transformations are accurate and we have reason to believe they are, then length contraction resulting from the motion of an object does not have to be relative to any observer. It is relative to the real velocity of the object.

    While it is true that without an observer and some mechanism to determine which of two frames of reference is in motion, we cannot know if an object is in motion, if it is in motion according to the Lorentz transformations it is length contracted. An object in motion is length contracted according to the Lorentz transformations.

    How two observers in relative motion to one another, perceive each other is a matter of perspective. Each will see the other as length contracted. To know which is length contracted you have to know which one is in motion or if both are in motion and the velocity at which they are moving.

    At present we have no way to determine if there is an absolute rest frame of reference, so length contraction can only be measured relative to an observer at assumed to be at rest or with a know velocity.
     
  19. Janus58 Valued Senior Member

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    Distance to the Sun as measured by the Earth:
    150,000,000 km
    speed of muon relative to the Earth:
    0.9999c
    Time for muon to travel from Earth to Sun as measured by the Earth:

    t= 150,000,000 km/0.9999c = ~8 min 20 sec

    [/quote]
    No, it was measured on the Earth:τ = 2 × 10^-6s[/QUOTE]

    Are you completely incapable of reading anything in context?

    The "measured on the Earth" lifetime of 2e-6 sec is measured for a muon at rest with respect to the Earth in the lab. (or at least having speed relative to the lab small enough for relativistic effects to be insignificant.). This would also translate to the lifetime that the muon would measure for itself.

    However, in this example, the muon is moving at 0.9999c relative to the Earth, and so as measured by the Earth's clock, would be time dilated and live for 0.00014 sec.

    By the muon's own clock the lifetime would still only be 2e-6 sec.
     
  20. Emil Valued Senior Member

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    2,789
    No, measured velocities of the muon was β=0.9999.
    This velocities it seems to you: "...having speed relative to the lab small enough for relativistic effects to be insignificant."
     
  21. Janus58 Valued Senior Member

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    For crying out loud. The 0.9999c velocity was for the muons created by cosmic ray collisions in the upper atmosphere. They have such high velocities because of the high energy of the collisions.

    The 2e-6 lifetime was for muons created in a lab at much lower energies and much lower velocities. It's not as if all muons travel at 0.9999c the instant that they are created.
     
  22. Emil Valued Senior Member

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    So you maintain that there are two types of muons:slow muons and fast muons?
     
  23. AlphaNumeric Fully ionized Moderator

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    No, there are muons and just like electrons (since all they differ by is mass) they can be accelerated or decelerated using electromagnetic fields. The ATLAS detector at CERN includes muon calorimeters, which slows them down and measures their energy as a result.

    Do some reading! All you're doing is displaying your ignorance and unwillingness to learn anything.

    You've repeatedly ignored my post about time dilation in journeys between the Earth and Sun. So much for all those 'good faith' comments you made. You have no good faith yourself.
     

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